In recent years, projectors (projection display units) configured to project an image onto a screen are widely used not only in offices but also in households. The projectors modulate light from a light source with use of a light valve to generate image light, and project the image light onto a screen to thereby perform display (for example, refer to PTLs 1 and 2). Recently, palm-sized ultra-compact projectors, mobile phones with a built-in ultra-compact projector, and the like are being introduced.